Goose parvovirus (GPV; also called Derzsy's Disease) and Muscovy duck parvovirus (MDPV) are antigenically distinct viruses that affect palmipeds. GPV is highly contagious and is characterized by multiple clinical signs, including anorexia, prostration, weakness and polydipsia. GPV may present in acute, subacute or chronic forms; the acute form of the disease may cause 100% mortality in goslings under 10 days of age. GPV primarily affects geese and Muscovy ducks (Cairina moschata). Currently, goose and Muscovy duck producers may protect against GPV using an attenuated live vaccine.
MDPV is an acute systemic infection of Muscovy ducklings. The clinical signs of MDPV are similar to those of GPV and the mortality rate can be 80% or higher. MDPV is transmitted horizontally and can also be transmitted vertically when susceptible hens become infected during lay or if there is reactivation of latency. To date, MDPV is known to affect only Muscovy ducks while other avian species are not susceptible. No attenuated live vaccine currently exists for combatting MDPV although an inactivated vaccine is available.
Accordingly, Muscovy ducks are vulnerable to both GPV and MDPV. Given the similarity with which both diseases present, it is difficult to determine which vaccine to administer, as the vaccine for GPV is ineffective against MDPV and the MDPV vaccine is ineffective against GPV. Muscovy duck producers may then administer vaccines against both diseases or face the economic hardship associated with the above-mentioned mortality rates.
Administering two vaccinations is less than ideal for logistical and economic reasons.